Crank-case construction



Mam 1,1927

G. D. ANGLE CRANK GASECONSTRUCTION Fi ed 13% so. 1920 2 Sheets-Sheet 1 March 1 y G. D. ANGLE CRANK CASE] CONSTRUCTION Filed Dec. (50, 1920 2 Sheets-Shoot 2 III/l/l/z Patented Mar. 1, 1927.

' UNITED STATES GLENN D. ANGLE, OF DAYTON, OHIO.

CRANK-CASE CONSTRUCTION.

Application filed December 30, 1920. Serial No. 434,130.

This invention relates to crank cases for internal combustion engines. The object of the invention is to provide greater rigidity for the engine assembly in all directions, simplify manufacturing, and add to the general appearance of the engine as a whole.

The. conventional engine in use at this time has a ledge extending practically the entire length of the uppersection of the crank case, the lower edge being at the center line of the crank shaft, said ledge resting on a supporting framework and being bolted thereto. The bolts for the flange of the lower section of the crank case are located between such supporting framework and the exterior walls of the crank case making it necessary to provide external stiffening ribs and for that purpose cores are frequently required to produce such ribs in a casting process. The ribs with holding down bolt bosses are usually located in line with the main bearings and transverse walls. It is possible under such conditions for considerable weave or deflection to occur between the holding down points, and a number of cases are known where metal had to be added to the ledge and sometimes to the ribs in order to eliminate breakage. Another objection to thistype of support has been the springing of the ledge which is usually boltedto a framework forming a wavy surface if such supporting member is of wood. It is then difficult to mount another engine on the same supporting frame unless such frame is covered with'a strip of steel.

Under the construction herein contemplated the main crank case walls tie into the supporting ledges at the outside thus placing all stiffening ribs and hold down bolt bosses inside. As a result the main crank compartment walls are in a most suitable position to resist torque and also to prevent lateral and longitudinal deflection. This is assisted somewhat by making the outside lines of the crank case on a radius or as nearly so as possible. The lines of appearance are only broken by the pockets for the hold down bolt nuts which are obviously in an ideal position from the point of view of strength. While the attached drawings show double transverse webs tied into the side walls and ledges, it will be obvious that when a single transverse web is used the same beneficial results will be obtained.

With the above and other objects in view the invention consists in the novel construction, combination and arrangement herein fully described, illustrated and claimed.

1n the accompanying drawings Figure 1 is a transverse section through the crank case of an internal combustion engine illustrating the improved structure;

Figure 2 is a fragmentary plan view thereof showing one of the pockets for the holding down devices;

Figure 3 is a fragmentary vertical section thereof on a large scale;

Figure 4 is a fragmentary vertical section showing the way of fastening the upper and lower sections of the crank case together;

Fig. 5 is a vertical sectional detail taken on line 5 5 of Fig. 1 looking in the direction of the arrows.

The improved crank case embodies an upper section A and a lower section B, said sections being normally fastened together by means hereinafter described. The upper section of the crank case comprises longitudinally extending supporting ledges 10 at opposite sides thereof, the bottom surfaces of said ledges being usually on a level with the center of the crank shaft of the engine. Extending from the outside of one supporting ledge 10 to the outside of the opposite supporting ledge is an arch 11 which is a substantially semicylindrical wall 11, form-.

ing the main body of the upper section of the crank case, said Wall forming the top wall of the crank case and also the side walls thereof as clearly shown in the drawings. The upper section of the crank case also comprises normally vertical transverse webs 12 which, it willbe observed in the drawings, tie into or are'formed integrally with the body 11 and consequently the top and side walls of the upper section of the crank case and also the supporting ledges 10. The ledges 10 extend inwardly in the form of flanges, as shown, the bottom surface of such ledges and flanges being in line with the center of the crank shaft of the engine.

Approximately in transverse alignment with the webs 12 and at oppositesides of the crank case, the ledges 10 of the latter are formed with re-entrant pockets 18. T hesc pockets are formed at the bottom with bosses 14 to receive the nuts 15 on the upper ends of the bolts 16 which extend through the ledges 10 and downwardly through the engine support the latter belng shown 1n this instance as consisting of the usual enginebearers or beams 17. The same structure and arrangement may be employed with a single web construction instead of the double web construction as shown in Figure 2.

In order to provide for attaching the lower section of the crank case to the upper section thereof, the upper section being usually formed of aluminum, duralurnin or analagous material, comparatively hard metal bushings 18 are inserted through holes in the ledges 10 as shown in Figure 4 and securely fastened therein as by screw threading or otherwise. Said bushings 18 are intern-ally threaded as shown to receive the cap screws 19 which are inserted through flanges 20 on the lower section of the crank case upwardly into the bushings 18.

From the foregoing description taken in connection with the drawings it will now be apparent that the main crank chamber walls tie into the supporting ledges at the outside thus enabling all the stiffening ribs and hold down bolt bosses to be placed inside. Thus the main compartment walls are in a most suitable position to resist torque and also to preventlateral and longitudinal deflection. The outside lines of the crank case are broken only by the pockets for the hold down bolt nuts which are obviously in ideal position from the point of View of strength.

I claim:

1. In an engine crank case, an upper crank case section comprising a substantially semicylindrical body forming the top and side walls of such upper section, supporting ledges extending from the bottom edges of said body inwardly and having their bottom surfaces in line with the center of the engine crank shaft, and webs extending transversely within said body and serving to tie together said top and side walls of the body and the said ledges.

2. In an engine crank case, an upper crank case section having a pair of side walls, a. lower crank case section having side walls spaced apart a distance substantially less than the distance between the side walls of the upper section, the side walls of the upper section having ledges integral therewith projecting inwardly therefrom to provide a face for the attachment of said lower section and for attachment to engine bearers below the sides of the upper section, the side walls of said upper section having reentrant pockets for the reception of engine bearer bolts, and laterally extending walls inwardly bracing the side walls of the upper section at said pockets.

3. In an engine crank case, an upper crank case section having a pair of side walls, a lower crank case section having side walls spaced apart a distance substantially less than the distance between the side walls of the upper sect-ion, the side walls of the upper section having ledges integral therewith projecting inwardly therefrom to provide a face for the attachment of said lower section and for attachment to engine bearers below the sides of the upper section, the side walls of said upper section having reentrant pockets for the reception of engine bearer bolts, and laterally extending walls inwardly bracing the side walls of the upper section at said pockets and made integral with said side walls.

4. In an engine crank case, an upper crank case section comprising longitudinally extending top and side walls having inwardly ofi'set portions onthe opposite sides of the crank case to which the lower crank case section may be secured, leaving lateral parts of said portions for supporting said crank case, re-entrant pockets in said ledges providing a place for passing fastening means through said ledges into engine bearing supports, and laterally extending bracing walls at said pockets inside said upper crank case section.

In testimony whereof I have afiixed my signature.

GLENN D. ANGLE. 

